1. Field of the Invention
The present invention relates to an electrically operated power steering device that is employed in a vehicle such as an automobile or the like.
2. Description of the Related Art
In an electrically operated power steering device of a certain type, a rotational shaft of an electric motor is rotationally driven so as to apply a steering assist force to a steering shaft. The electrically operated power steering device of this type is disclosed, for example, in Japanese Patent Publication Laid-Open No. HEI 8-163889.
However, according to the electrically operated power steering device of the aforementioned type, a stator of the electric motor is provided with a yoke portion with which teeth portions are integrated, and coils are wound around the teeth portions. Besides, the stator is securely fixed within a housing. Thus, the yoke portion and the housing have a double structure, and the overall diameter is comparatively large. On the contrary, if an attempt is made to reduce the size of the electric motor without changing the above-described structure, it is necessary to make the teeth portions and the yoke portion compact. In this case, it is impossible to ensure sufficient output torque of the electric motor. In other words, the aforementioned electrically operated power steering device makes it difficult to ensure sufficient output torque of the electric motor and to reduce the size of the electric motor.